JPH03116532A - Optical disk device - Google Patents

Abstract

PURPOSE:To prevent double writing without fail and to prevent the reliability of recording data from being lowered by comparing reflected light from the optical disk of a pulse-shaped recording light beam with a prescribed threshold level and stopping recording operation when the counted value of the pulse lower than the prescribed level is more than the prescribed level. CONSTITUTION:The pulse-shaped recording light is radiated from a light output means 5 and the reflected light is compared with the prescribed level. Then, the pulse less than the prescribed level is detected by a detecting means 30 and the number of the pulses less than the prescribed level is counted by a counting means 31. When the counted value is more than the prescribed value, it is judged that the area is a recorded area, and the recording operation is stopped. In such a case, a microprocessor 36 detecting a record prohibiting signal S9 is made active codes a signal (stop signal) showing such a state and sends out the signal to a host device 37. Thus, double writing is prevented without fail and the reliability of the recording data can be prevented from being lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an optical disc device for recording and reproducing information on and from an optical recording medium such as an optical disc.

(Prior Art) Conventionally, in an information recording device such as an optical disk device that optically records or reproduces information on an optical recording medium such as a write-once or erasable optical disk, a semiconductor laser (optical output The information on the optical disc is read using a relatively small continuous optical output from the optical disc, while the information is recorded on the optical disc using an intermittently changing optical output of a relatively large predetermined value or more. Therefore, if an optical disc is irradiated with a light output that exceeds the above-mentioned predetermined value, even if it is not intended to be recorded, undefined information will be written on the optical disc, destroying information that has already been recorded. become.

For example, Japanese Patent Application No. 10097/1983 discloses methods for preventing the destruction of information already recorded on such optical discs.
There are some disclosed in 6.

This method determines that double writing has occurred when a bit is detected in the reproduced signal during recording.

FIG. 4 shows a waveform of light reflected from an optical disc in such an optical disc device. FIG. 4(a) shows a reflected light waveform during reproduction. A relatively small prior output is obtained, and a low-level portion (dark portion) exists at a position corresponding to a bit, and this becomes significant data. FIG. 5B shows a reflected light waveform in a normal state, that is, when data is recorded in a non-recording area.

A pulse-like waveform with a relatively large optical output corresponding to the recorded data can be obtained. Furthermore, the same figure (C) shows the reflected light waveform at the time of double writing. A waveform is obtained in which the reflected light waveform during reproduction and the reflected light waveform during normal recording are superimposed. Then, the reflected light waveform shown in FIG. 4(c) is compared with a predetermined threshold level Th, and when the presence of a bit (dark area) is detected, double writing is determined. In other words,
Depending on whether the playback signal during recording contains a signal corresponding to the bit, it is determined whether the area currently being recorded is an unrecorded area or a recorded area, and double writing is prevented. It is supposed to be done.

However, the playback signal during recording becomes unstable due to the influence of, for example, undershoot of the recording beam, resulting in false detection or omission of detection, which has the disadvantage that double writing cannot be reliably prevented. Ta. To solve this problem, there is a method that counts the reproduction signals that do not reach a predetermined level among the reproduction signals during recording, and determines that double writing has occurred when this counted value exceeds a predetermined value. However, this is designed to destroy low recording data until the predetermined value is reached. At this time, the amount of recorded data destroyed can be kept within the error correctable range, but when partially destroyed recorded data is to be completely reproduced, it is essential that the error correction circuit operates normally. There is a drawback that the reliability of recorded data is undeniably lowered.

(Problems to be Solved by the Invention) As described above, the present invention attempts to prevent double writing by detecting whether it is an unrecorded area or a recorded area using a reproduction signal during recording. However, the number of playback signals that do not reach a predetermined level is counted among the playback signals during recording, and when this count exceeds a predetermined value, it is determined that double writing has occurred and the double writing is performed. A device that ensures reliable detection is being considered, but since this destroys low recorded data until the above predetermined value is reached, the amount of recorded data destroyed can be kept within the range where errors can be corrected. When completely reproducing recorded data that has been destroyed, it is essential that the error correction circuit operates normally, and this was done in order to eliminate the drawback that the reliability of the recorded data is undeniably reduced. It is an object of the present invention to provide an optical disc device that can reliably prevent double writing by preventing erroneous detection or omission of detection, and can also prevent a decrease in the reliability of recorded data.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, an optical disk device of the present invention includes an optical recording medium for recording information and a pulsed recording light beam on the optical recording medium. A light output means for emitting light, a detection means for detecting the reflected light of the recording light beam emitted from the light output means, and a counter for counting the number of pulses in which the reflected light detected by the detection means is below a predetermined level. means, and a control means for stopping emission of the recording light beam from the light output means when the counting means counts a predetermined value;
a first processing means for outputting stop information indicating that the emission of the green light beam from the control means has been stopped; and second processing means for recording information recorded in the area irradiated with the recording light beam from the optical recording medium and information intended to be recorded in this area, respectively, in other areas of the optical recording medium. It is characterized by

(Function) According to the present invention, the magnitude of the reflected light of the pulsed recording light beam output from the light output means is different depending on whether it is reflected from a recorded edge area or from an unrecorded area. This system detects double writing by utilizing this property and notifies an external device of this detection result.A pulsed recording light beam is emitted from the optical output means, and the reflected light of this pulsed recording light beam is The detection means detects pulses below a predetermined level by comparing the pulses with the level of The recording operation is stopped when it is determined that the area is a border area.

Further, along with the stop of this recording operation, the control means outputs a stop signal indicating double writing to the second processing means via the first processing means, and the second processing means stops the recording operation. It receives the signal, reads out the partially destroyed data recorded in the double-written area of the optical recording medium, re-records it in another area, and also separates the data that was about to be recorded. The data is recorded in this area. In this way, since the magnitude of the reflected light of the recording light beam is detected, which is relatively stable, stable detection is possible, and double writing is determined after detecting multiple reflected lights below a predetermined level. This makes it possible to reliably prevent double writing, and furthermore, even if the data is within the correctable range, partially destroyed data is re-recorded in another area, thereby reducing the reliability of the recorded data. It is possible to prevent this.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disc device of the present invention. In the figure, an optical disc (optical recording medium) 1 is
For example, the surface of a circularly shaped substrate made of glass or plastic is coated with a donut-shaped metal coating layer such as tellurium or bismuth.

The optical disc 1 is rotated by a spindle motor 2. This spindle motor 2 is
A motor control circuit (not shown) that operates in response to a control signal from the control circuit 3 controls the start and stop of rotation, the number of rotations, and the like.

The control circuit 3 is composed of, for example, random logic, and includes circuits for controlling the rotation of the spindle motor 2 as well as various other controls to be described later.

An optical disc 4 is disposed below the optical disc 1 . The optical disc 4 records or reproduces information on the optical disc 1, and includes a semiconductor laser oscillator 5, a collimator lens 6, and a polarizing beam splitter 7.
, objective lens 8, cylindrical lens 9 and convex lens 1
The astigmatism optical system includes a well-known astigmatism optical system 11, a 4-split photodetector 12, a photodetector 13, and the like. The optical head 4 is disposed so as to be movable in the radial direction of the optical disc 1 by a moving mechanism (not shown) constituted by, for example, a linear motor, and is configured to record or reproduce objects according to control signals from the control unit 3. It is now possible to move to the target track.

The semiconductor laser oscillator 5 generates a diverging laser beam (light beam) according to the drive signal S1 from the optical output control circuit 14, and transmits information to the recording film 1 of the optical disc 1.
When recording on the optical disc 1, a strong laser beam whose light intensity is modulated according to the information to be recorded is generated, and when information is read and reproduced from the recording film 1a of the optical disc 1, the laser beam has a constant light intensity. It is designed to generate weak laser light.

The diverging laser beam generated by the semiconductor laser oscillator 5 is converted into a parallel beam by a collimator lens 6 and guided to a polarized beam splitter. The laser beam guided by the polarized beam splitter passes through the polarized beam splitter 7 and enters the objective lens 8, and is focused by the objective lens 8 toward the recording film 1a of the optical disc 1.

The objective lens 8 is supported movably in the direction of its optical axis by a lens actuator 15 as a lens drive mechanism. The objective 1. is moved in the optical axis direction by the servo signal S2 from the focus servo circuit 16. The focused laser beam passing through the lens 8 is projected onto the surface of the recording film 1a of the optical disc 1, so that the minimum beam spot is formed on the surface of the recording film 1a of the optical disc 1. In this state, the objective lens 8 is in a focused state.

The objective lens 8 is also movable in a direction perpendicular to the optical axis, and is moved in the direction perpendicular to the optical axis by a servo signal from a tracking servo circuit (not shown). It has become. Then, the focused laser beam that has passed through the objective lens 8 is projected onto the surface of the recording film 1a of the optical disc 1, and is irradiated onto the recording tracks formed on the surface of the recording film 1a of the optical disc 1. It has become. In this state, the objective lens 8 is in a matching track state. In the focused point and focused track state, information can be written and read.

On the other hand, the diverging laser beam reflected from the recording film 1a of the optical disk 1 is converted into a parallel beam by the objective lens 8 when it is focused, and is returned to the polarized beam splitter again. Then, it is reflected by this polarizing beam splitter 7 and guided onto a 4-split photodetector 12 by an astigmatism optical system 11 consisting of a cylindrical lens 9 and a convex lens 10, and an image is formed in a state where defocus appears as a change in shape. It is now possible to do so. The four-split photodetector 12 is composed of four photodetection cells that convert the light imaged by the astigmatism optical system 11 into electrical signals.

Two sets of signals output from two photodetection cells arranged diagonally with each other in this four-split photodetector 12 are supplied to amplifiers 17 and 18, respectively.

The focus servo circuit 16 includes an error amplifier 19 that inputs the two signals amplified by the amplifiers 17 and 18 and performs error amplification, a phase correction circuit 20 that corrects the phase of the output signal of the error amplifier 19, and a phase correction circuit 20 that corrects the phase of the output signal of the error amplifier 19. An analog switch 21 that controls whether or not to supply the output signal of the circuit 20 to the driver 22, and a driver 2 that amplifies the signal from the analog switch 21 and drives the actuator 21.
2. When this analog switch 21 is turned on by the focus on/off signal S3 from the control circuit 3, a focus servo loop is formed by supplying the signal from the phase correction circuit 20 to the actuator 15 via the driver 22. It has become so.

Further, the output signals from the amplifiers 17 and 18 are supplied to an adder 23. The signal added by the adder 23 reflects the recorded content of the optical disc 1, and is output as a waveform signal as shown in FIG. In other words, during normal recording in a non-recording area, a signal with a signal level that is several times higher than the signal level during reproduction is obtained, as shown in FIG. 3(a), but in a low recording area, When performing so-called double writing, the third
As shown in Figure (b), many signals having a signal level several times higher than the signal level during reproduction can be obtained. this is,
This is because the recording light beam is irradiated onto a portion where a bit has already been formed, so the amount of reflected light is reduced at that bit portion. The output signal of the adder 23 having such a waveform is sent to the binarization circuit 24.

The binarization circuit 24 is composed of, for example, a comparator, and performs binarization by comparing the analog signal output from the adder 23 with a predetermined threshold level Th. This threshold level Th is set as a signal that is lower than the reflected light signal level when recording is performed in an unrecorded area, and higher than the reflected light signal level when recorded in a low recording area. The reflected light signal S binarized by this binarization circuit 24
4 is supplied to the detection circuit 30.

The detection circuit 30 detects the recorded data S11 and the binarization circuit 2.
The reflected light signal S4 outputted from 4 is inputted thereto, and a double writing detection signal S8 is generated. That is, if the optical disc 1 to be recorded is unrecorded, a significant signal should be obtained from the binarization circuit 24 corresponding to the recorded data 5ll (SIO). Therefore, the detection circuit 30 checks whether the recorded data S11 and the reflected light signal S4 from the binarization circuit 24 have a one-to-one correspondence.
When the reflected light signal S4 corresponding to ll is not obtained, a double writing detection signal S8 is output. The double writing detection signal S8 from this detection circuit 30 is supplied to a counter circuit 31.

The counter circuit 31 counts the number of occurrences of the double write detection signal S8 outputted by the detection circuit 30, and outputs a recording prohibition signal S9 when the number exceeds a predetermined value. When it is detected that the value exceeds a predetermined value, a recording prohibition signal S9 is generated.
The reason for this is that if there is a part of the optical disc 1 where the reflective film is missing from the beginning, such as a pinhole, the double writing detection signal S8 will be output even if it is an unrecorded area, which may cause an error. This is because it will result in detection. The above predetermined value is determined as follows. In other words, the upper limit of the predetermined value is regulated by the burst error correction capability of the device. This is because recording must be stopped before data destroyed by double writing can be repaired by an error correction circuit (not shown). On the other hand, the lower limit of the predetermined value is determined by the allowable range of defects such as pinholes on the optical disc 1. In other words, optical disc 1
While recording is being performed in the defective area above, the double writing detection signal S8 continues to be output, but if the recording prohibition signal S9 is output before passing through the defective area, a false detection will result, so this is acceptable. The predetermined value must be greater than the minimum possible value. The recording inhibit signal S9 from the counter circuit 31 is supplied to the AND gate 33 and also to the microprocessor 36 which controls the recording of information. Further, the counter circuit 31 is supplied with a clear signal S12 generated by the control circuit 3 in response to a control signal from the microprocessor 36 to reset the counter. Note that control signals between the control circuit 3 and the microprocessor 36 are transmitted and received via a data bus (or interface bus) 36.

The microprocessor 36 sends and receives information to and from the control circuit 3, and also sends and receives various information to and from a host device 37 as an external device. For example, the microprocessor 36 that detects that the recording prohibition signal S9 has become active encodes a signal (stop signal) indicating this and sends it to the host device 37.

The AND gate 33 receives recording data S10 supplied from the host device 37 via the control circuit 3 as one input, and
Recording data Sl whose inhibition/permission is controlled by using the recording inhibition signal S9 outputted by the counter circuit 31 as the other input
It outputs l. This recorded data Sll is stored in the waveform shaping circuit 32, the detection circuit 30. and counter circuit 31
is being supplied to. The waveform shaping circuit 32 is
It formats the recording data S11 and supplies it to a driver 28, which will be described later.

Further, a photodetector 13 constituted by a photoelectric conversion element such as a photodiode, which is provided facing a light emitting port opposite to a light emitting port for recording or reproducing laser light of the semiconductor laser oscillator 5, is configured by a photoelectric conversion element such as a photodiode. When the monitor light from the laser oscillator 5 is irradiated, the monitor light is converted into an electric signal (photocurrent) and supplied to the light output control circuit 14 as the light output monitor signal S5 of the semiconductor laser oscillator 5. ing.

The optical output control circuit 14 controls the optical output of the semiconductor laser oscillator 5 to keep it constant by inputting the optical output monitor signal S5 output from the semiconductor laser oscillator 5 and performing feedback control. That is, the current-voltage conversion circuit 25 inputs the optical output monitor signal S5 photoelectrically converted by the photodetector 13 and extracted as a current signal, and converts the light intensity received by the photodetector 13, that is, the output of the semiconductor device the oscillator 5. It converts into a voltage signal S6 corresponding to the optical output and outputs it. A voltage signal S6 outputted from this current-voltage conversion circuit 25 is supplied to an error amplifier 26.

The error amplifier 26 uses the voltage signal S6 as one input and the reference voltage Vs generated by a constant voltage source (not shown) as the other input, compares the two types of pressures S6 and Vs, and amplifies the difference. This is output as an error signal. The reference voltage Vs is a constant voltage for obtaining the optical output necessary for reproduction, and the voltage signal S6 is converted to the reference voltage Vs.
By feedback control to bring it closer to
A constant optical output can be obtained from the semiconductor laser oscillator 5. The error signal from the error amplifier 26 is supplied to a driver 28.

The driver 28 is supplied with a recording pulse signal S7 corresponding to the information to be recorded from the above-mentioned waveform shaping circuit 32, so that the optical output for recording is output from the semiconductor laser oscillator 5. It is now possible to do so. Note that the voltage signal output from the error amplifier 26 is input to the driver 28 during reproduction, and the voltage signal output from the error amplifier 26 is input to the driver 28 during recording.
A voltage signal is input in which the voltage value input during the previous playback is held in a sample-and-hold circuit (not shown), and these two inputs can be switched depending on whether recording or playback is being performed. It has become. In both recording and reproduction, feedback control is performed based on the level of optical output during reproduction.

Next, the operation of suppressing double writing during recording in the optical disc device configured as described above will be described with reference to the timing chart of FIG. 2.

First, before performing a recording operation, an initial operation is performed to check the validity of the light emission output of the semiconductor laser oscillator 5. In other words, the focus on/off signal S3 is sent from the control circuit 3.
By outputting , the analog switch 21 is turned off. This disconnects the focus servo loop and
The objective lens 8 is released from forcing control.

Next, a signal (not shown) for forcibly moving the lens actuator 15 is supplied from the control circuit 3 to the lens actuator 15 via the driver 22 . As a result, the objective lens 8 is forcibly moved to the position shown by the dotted line in FIG. 1, creating a defocused state. In this defocused state, power is supplied to the optical output control circuit 14 to turn on the semiconductor laser oscillator 5 and start outputting a laser beam. As a result, the monitor light generated from the semiconductor laser oscillator 5 is converted into a current according to the light output by the photodetector 13 and output as a light output monitor signal S5. The current-voltage conversion circuit 25 converts this optical output monitor signal S5 into a voltage signal S6,
Error amplifier 26 is supplied.

In the error amplifier 26, a preset reference voltage Vs
and the voltage signal S6, and output the error amount as an error signal. This error signal is a signal that reduces the optical output of the semiconductor laser oscillator 5 if the voltage signal S6 is greater than the reference signal VsJ, and increases the optical output of the semiconductor laser oscillator 5 if the voltage signal S6 is less than the reference signal VsJ. By supplying this error signal to the driver 28, a feedback loop is formed and the reference voltage Vs and the voltage signal S6 are
The optical output of the semiconductor laser oscillator 5 is thereby kept constant.

Next, the control circuit 3 drives the actuator 15 via the driver 22 to move the objective lens 8 toward the in-focus position. When it is detected that the in-focus position has been reached, the analog switch 21 is turned on, the focus servo loop is connected, and the initial operation is completed. Thereafter, automatic focus control is performed by a focus servo loop, and normal operations such as reading and writing information from the optical disc 1 are performed.

In this state, as shown in Figure 2(a),
In response to the recording data sent from the host device 37 via the microprocessor 36, the control circuit 3 outputs pulsed recording data SIO. At this time, the recording inhibit signal S9 output from the counter circuit 31 is initially set to a high level by supplying the clear signal S12 from the control circuit 3. Therefore, the recorded data S
IO is supplied to the waveform shaping circuit 32 via the AND gate 33 and further supplied to the driver 28. As a result, the semiconductor laser oscillator 5 emits intermittent high-output laser light according to the recording data S10. This laser beam is converted into a parallel beam by a collimator lens 61 and guided to a polarized beam blur. This polarizing beam splitter 71; the guided laser light passes through the polarizing beam splitter 7, enters the objective lens 8, and is focused by the objective lens 8 toward the recording film 1a of the previous disk 1. As a result, bits are formed on the recording film la and information recording is performed.

On the other hand, the diverging laser beam reflected from the recording film 1a of the optical disk 1 during the recording operation is converted into a parallel beam by the objective lens 8, and returned to the polarized beam splitter again. Then, it is reflected by this polarizing beam splitter 7 and imaged onto a four-split photodetector 12 by an astigmatism optical system 11 consisting of a cylindrical lens 9 and a convex lens 10 . At this time, the optical disc 1 that is being written to
If the area has already been recorded, reflected light waveforms with different light intensity levels are obtained, as shown in FIG. 2(b). Signals photoelectrically converted by this four-split photodetector 12 are supplied to amplifiers 17 and 18, respectively. and,
One of the signals amplified by the amplifiers 17 and 18 is supplied to the focus servo circuit 16 below the error amplifier 19 and used for focusing control. Further, the other of the signals amplified by the amplifiers 17 and 18 is supplied to the adder 23 to perform addition, and then supplied to the binarization circuit 24.

As shown in FIG. 3, the binarization circuit 24 includes the adder 2
By comparing the signal from 3 with a predetermined threshold level Th, a binarized reflected light signal S4 as shown in FIG. 2(c) is output. At this time, the reflected light of the laser beam irradiated onto the pits that have already been formed is small, so it does not appear as significant data (Figure 2 (C)
) middle dotted line part). This reflected light signal S4 is then supplied to the detection circuit 30.

The detection circuit 30 includes a flip-flop (not shown), which is set at the rising edge of the recording data 811 output from the AND gate 33 and reset at the rising edge of the reflected light signal S4. It is.

The output of this flip-flop is output from the detection circuit 30 as a double write detection signal S8, as shown in FIG. 2(d).

The counter circuit 31 inputs the double write detection signal S8, captures the level of the double write detection signal S8 at the falling edge of the recording data Sll, which is the other input, and outputs a count pulse of a built-in counter (not shown). (Figure 2 (
e). This count pulse is counted by a counter, and when a predetermined value is counted, the recording prohibition signal S9 is set to a low level. As a result, one input of the AND gate 33 becomes low level, and the output of the recording data 810 is suppressed. Therefore, from then on, the recording data Sll is not output, the output of the waveform shaping circuit 32 is also suppressed, and recording on the optical disc 1 is prohibited. The recording prohibition state is set to the control circuit 3 by a command from the microprocessor 36.
This will be maintained until the clear signal S12 is output. This prevents double writing. Further, since the record inhibit signal S9 is also supplied to the microprocessor 36, when the microprocessor 36 receives the record inhibit signal S9, it notifies the host device 37 that double writing has occurred.

Thereafter, the host device 37 notifies the operator by displaying, for example, on the display of the host device 37 that double writing has occurred, and also transfers the data of the block in which the double writing occurred on the optical disk 1 to other blocks on the optical disk 1. The microprocessor 36 is instructed to re-record the data. The microprocessor 36 follows instructions from the host device 37.
The host device 37 of the optical disc 1 reproduces the data of the partially destroyed block while correcting the error.
The process of re-recording to another block as instructed by is performed.

In this way, instead of immediately determining that double writing is occurring when a small amount of reflected light from the optical disc 1 is detected, it is determined that double writing is occurring when a predetermined number or more of small amounts of reflected light are detected. This makes it possible to significantly reduce false positives and missed positives.

Furthermore, until a predetermined number or more of small reflected light beams from the optical disc 1 are detected, the data in the low recording area will be destroyed, but the amount of data destroyed is set so that it is within the error correctable range. The recorded data can be played back. However, the reliability of the partially destroyed data has decreased, and it is not guaranteed that the data can be stably reproduced in the future. Therefore, as mentioned above, under the instructions of the host device 37, the microprocessor 3
By reproducing the data partially destroyed by No. 6 and recording it again in another block in an error-free state, the reliability of the recorded data is maintained at a high level.

As described above, when the pulsed recording light beam output from the semiconductor laser oscillator 5 is reflected by the optical disc 1, the magnitude of the reflected light differs between when it is reflected from an already recorded area and when it is reflected from an unrecorded area. Taking advantage of the property that the pulsed recording light beam is different from that when reflected from the optical disc 1, the semiconductor laser oscillator 5 emits a pulsed recording light beam, and this pulsed recording light beam adjusts the reflected light reflected by the optical disc 1 to a predetermined threshold level. The detection circuit 30 detects pulses below a predetermined level from this binarized signal, and the counter circuit 31 counts the number of pulses below the predetermined level. When the value exceeds this value, it is determined that the area is a low recording area and the recording operation is stopped, so the size of the reflected light of the recording light beam, which is relatively stable, is detected. In addition to being able to perform stable detection, since double writing is determined after detecting a plurality of reflected lights below a predetermined level, double writing can be reliably prevented. Furthermore, with the stop of the recording operation, the control circuit 3 outputs a signal indicating double writing to the microprocessor 36, and the microprocessor 36 further outputs a signal to the host device 37 as an external device to perform re-recording. Upon receiving instructions from the host device 37, the microprocessor 36 reproduces the data in the block where the double writing occurred and rerecords it in another block with an error in it. This prevents a decrease in reliability.

Note that in the above embodiment, the recorded data 510 (S11)
The detection circuit 3 uses the rising and falling edges of
0. The case where the counter circuit 31 etc. are operated has been explained, but since the phase of the recording data SIO (Sll) and the reflected light signal S4 changes depending on the recording method and the configuration of the waveform shaping circuit 32, etc., If the operation timing is changed as appropriate depending on the configuration of the waveform shaping circuit 32, the same effects as in the above embodiment can be achieved.

[Effects of the Invention] As detailed above, the present invention provides an optical disc device that can prevent false detections and omissions, reliably prevent double writing, and prevent a decrease in the reliability of recorded data. can do.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a block diagram showing a schematic configuration of an optical disk device.
Figure 2 is a timing chart for explaining the operation, Figure 3 is a diagram for explaining the state of reflected light during normal recording and double writing, and Figure 4 is a diagram for explaining the conventional double writing prevention. FIG. 3 is a diagram for explaining the operation. 1... Optical disk, 2... Spindle motor, 3.
...Control circuit (control means) 4...Optical head, 5.
... Semiconductor laser oscillator (light output means), 8... Objective lens, 12... 4-split photodetector, 13... Photodetector, 14... Light output control circuit, 15... Lens Actuator, 25... Current-voltage conversion circuit, 24... Binarization circuit, 30... Detection circuit (detection means), 31...
- Counter circuit (counting means) 32... Waveform shaping circuit, 33... AND gate (control means), 35... Data bus, 36... Microprocessor (first processing means), 37... - Host device (second processing means).

Claims (1)

[Scope of Claims] An optical recording medium for recording information, a light output means for emitting a pulsed recording light beam onto the optical recording medium, and a detection of reflected light of the recording light beam emitted from the light output means. a detection means for counting the number of pulses in which the reflected light detected by the detection means is below a predetermined level; a control means for stopping the emission; a first processing means for outputting stop information indicating that the emission of the recording light beam from the control means has been stopped; depending on,
a second processing means for recording the information recorded in the area irradiated with the recording light beam from the optical output means and the information intended to be recorded in this area, respectively, in other areas of the optical recording medium; An optical disc device characterized by comprising: